1. Field of the Invention
The present invention relates to a clutch disk for a motor vehicle friction clutch, having a hub couplable fixedly in terms of rotation to a transmission input shaft. Friction linings are provided in a radially outer region of the clutch disk. The friction linings lie, at least partially, essentially parallel to, or in one plane which is essentially orthogonal to, a hub rotation axis. The clutch further has a connecting arrangement, by means of which the friction linings of the clutch disk are connected to the hub so that the friction linings can execute a radial movement with respect to the hub rotation axis and/or a tilting movement with respect to the plane.
2. Description of the Prior Art
In vehicle construction, there is often the problem, where transversely installed drive assemblies are concerned, that a transmission input shaft is no longer mounted in a pilot bearing in the crankshaft and is therefore no longer centered with respect to the crankshaft. The result of this is that slight axial offsets and wobbling movements may occur during operation, which are induced by the untrue running of the crankshaft or of the flywheel fixed to the crankshaft.
When rigid clutch disks are used, in which the friction linings are coupled essentially rigidly to the hub of the clutch disk, the axial offset or the wobbling movement often gives rise to the problem of excessive wear in the region of the hub profile or of the transmission input shaft profile, or there is the problem that the welding or caulking between the hub and the driving disk carrying the friction linings fractures. Furthermore, the bearings, for example in the dual-mass flywheel and in the transmission, are subjected to greater load, and often there is poor vibration uncoupling which may lead to changing idling states.
German reference DE 43 22 578 A1 discloses a clutch disk in which a driving disk with an internal toothing is received on an external toothing of the hub of the clutch disk so that limited radial displaceability or relative rotation becomes possible between these two parts. Furthermore, the driving disk has arranged on it a spring element which presses against a bearing element supported on the hub and which thus causes the driving disk to be centered with respect to the hub.
German reference DE 44 16 949 C1 discloses a wobblable clutch disk in which the friction linings, that is to say lining springs of the latter, are connected to the clutch hub via a plurality of leaf-spring elements running essentially tangentially to the clutch hub.
Furthermore, French reference FR-A-27 24 995 discloses a clutch disk in which the lining carriers are fixed to the driving disk via bolts. The bolts are pivotable with respect to the driving disk by the interposition of elastic elements so that corresponding pivotability or displaceability of the lining carriers becomes possible.
The object of the present invention is to provide a clutch disk in which wobbling movements or axial offsets occurring during operation can be balanced out or compensated in a reliable way. According to a first embodiment of the present invention, this object is achieved in that, in a generic clutch disk, the connecting arrangement comprises a driving disk which is coupled essentially fixedly in terms of rotation to the hub, on the one hand, and the friction linings, on the other hand, and which, in a region radially between the coupling to the hub and the coupling to the friction linings, has at least one deformation region running in the axial direction or bent toward the axial direction.
Elasticity, which reliably and effectively permits wobbling movements and compensates axial offsets, is integrated into the clutch disk by the provision of this deformation region extending or bent in the axial direction.
This effect may be reinforced, particularly when the deformation region comprises a plurality of bend regions which provide an axially serpentine contouring running from radially inward to radially outward.
An easily practicable adaption of the clutch disks according to the invention to various requirements, that is to say the provision of various elasticities, may be implemented in a simple way, in that the driving disk has a radially inner annular region for coupling to the hub, a radially outer annular region for coupling to the friction linings and a plurality of connecting portions, and in that the deformation region is provided in each case in the region of the connecting portions. It is also advantageous, here, that weight can be saved by the provision of cutouts in the region of the driving disk.
Alternatively, however, it is also possible for the disk part to be an essentially completely closed diaphragm-like disk part. In this case, to, the elasticity can be selected by the choice of material, on the one hand, and by the special design of the meander-like structure, on the other hand.
The connecting portions may extend essentially radially.
According to a further independent aspect of the invention, there is provision for the connecting arrangement to comprise a disk part with a radially inner annular portion, a radially outer annular portion and a plurality of connecting portions. The connecting portions are bent from radially inward to radially outward and in at least one circumferential direction. Bending in the circumferential direction also allows highly constraint-free tilting or displacement in the radial direction, so that wobbling movements and axial offsets can be compensated.
Of course, it is also possible to combine this aspect with the previously specified aspects via the provision of three-dimensionally bent connecting portions.
Preferably, in this case, the connecting portions are approximately S-shaped.
According to a further embodiment of the present invention, the foregoing object can be achieved in that the connecting device comprises a driving disk which radially outwardly is coupled to the friction linings and radially has an internal toothing which meshes with an external toothing on the hub, radial movement play being provided. The device furthermore comprises a centering spring arrangement by means of which the driving disk is centered elastically with respect to the hub. A particularly simple design may be obtained, in this case, if the centering spring arrangement comprises at least one angularly designed centering spring portion which is supported on an outer circumferential surface of the hub.
In this case, there may, for example, be provision for the at least one angularly designed centering spring portion to be provided by at least one essentially ring-like spring part which has, on an inner circumferential region, a plurality of spring tabs which are bent in the direction of the hub rotation axis so as to bear on the outer surface of the clutch hub.
So that the axial securing function, in addition to radial centering, can also be integrated into the clutch disk in a simple way, in another embodiment that at least one spring part has at least one axial securing projection supported axially on a radial projection of the hub, preferably in the region of the external toothing.
Preferably, a spring part is arranged on each of the two axial sides of the driving disk.
The design may be simplified further and the number of parts reduced if the at least one spring part is designed integrally with the driving disk and forms a radially inner region of the latter.
In an alternative embodiment, the centering spring arrangement comprises at least one spring part fixed to one component, either the hub or the driving disk, which engages axially with at least one spring tab into an interspace formed between the internal toothing and the external toothing and which is supported under prestress on the other component. Since, in this case, the individual spring tabs engage into the region of the toothing, an embodiment which is axially extremely short is produced.
Here too, it is advantageous for the distribution of forces if a spring part is arranged on each side of the one component and the spring parts engage alternately from each of the two axial sides into an interspace between the external toothing and the internal toothing.
Furthermore, the at least one spring part may comprise at least one radially inward-projecting axial securing portion supported axially on the hub, preferably on the external toothing of the latter.
According to a further independent aspect, the object according to the invention is achieved in that the connecting arrangement comprises: an intermediate disk which is coupled to the hub for joint rotation and is displaceable with respect to the hub essentially radially to the hub rotation axis in a first direction of displacement. A driving disk is provided which, on the one hand, is coupled to the friction linings and, on the other hand, is coupled to the intermediate disk for joint rotation and is displaceable with respect to the intermediate disk essentially radially to the hub rotation axis in a second direction of displacement. The first direction of displacement and the second direction of displacement are different directions of displacement. A cardan-like coupling between the friction linings and the hub is provided here, which allows constraint-free and deformation-free radial displacement of the friction linings with respect to the hub. At the same time, preferably, the first direction of displacement is essentially orthogonal to the second direction of displacement.
This cardan-like coupling is provided, for example, in a clutch disk which comprises: at least one essentially radially extending for driving projection on one component, either the hub or the intermediate ring, and, on the other component, either the intermediate ring or the hub, so as to be assigned to each first driving projection, in each case an essentially radially extending first driving recess receiving the associated first driving projection with radial movement play. Additionally, on one component, either the intermediate disk or the driving disk, at least one essentially radially extending second driving projection is provided and, on the other component, either the driving disk or the intermediate disk, so as to be assigned to each second driving projection, in each case an essentially radially extending second driving recess is provided for receiving the associated second driving projection with radial movement play.
In this embodiment, too, it is advantageous, for unimpeded execution of the radial movement in any desired direction, if the at least one first driving projection and the at least one second driving projection are offset at approximately 90xc2x0 to one another in the circumferential direction.
According to a further independent aspect, the foregoing object is achieved in that the connecting arrangement comprises a radially projecting hub flange connected fixedly in terms of rotation to the hub. A driving disk is provided which radially outwardly is coupled to the friction linings and radially inwardly comprises two connecting portions, in each case a connecting portion being provided, at least in regions, on one axial side of the hub flange. A plurality of connecting bolts connect the connecting portions in each case to the hub flange for joint rotation, but allow radial relative movement and circumferential relative movement between the connecting portions, on the one hand, and the hub flange, on the other hand, to a predetermined extent. Between at least one of the connecting portions and the hub flange, an elastically deformable arrangement, preferably elastomeric material layer, is received under prestress.
In this case, there may, for example, be provision for the connecting bolts to be fixed with respect to the connecting portions or to the hub flange and to be displaceable in the radial and circumferential directions with respect to the other subassembly in each case. The deflection movement or displacement movement of the friction linings with respect to the hub, made possible by the elastically, may be further improved or made easier in that an elastically deformable arrangement is provided between the two connecting portions and the respectively associated axial side of the hub flange.
According to a further independent aspect of the present invention, the foregoing object is achieved in that the connecting arrangement comprises a torosional vibration damper arranged in the torque transmission path between the hub and the friction linings and having an input side and an output side. The input side and the output side are displaceable in the radial direction and/or axial direction with respect to one another and/or at least one of the sides, either the input side or the output side, being tiltable with respect to the plane and to the other side. In this case, advantageously, the torsional vibration damper, on the one hand, is utilized, for example, for damping torsional vibrations occurring in the idling speed range and, on the other hand, is utilized for providing the necessary movement play for the components movable relative to one another when wobbling movements or axial offsets occur. It is obvious that, if a torsional vibration damper is provided, the component regions coupled by means of the latter are also displaceable in the circumferential direction with respect to one another in order to perform the torsional vibration damping function. In this case, the relative movability in the radial direction and/or the axial direction then serves essentially to make a wobbling movement possible, and, at the same time, this radial displacement or axial displacement when torsion vibrations occur may also take place while a relative circumferential movement of the component groups is being executed. It may be pointed out that, here, insofar as an input side or an output side is referred to, this relates, for example, to the force flow or torque flow in the driving state of a drive assembly. It is obvious that, in the overrun mode, the functional assignment of the input side and output side to specific component groups may be reversed.
An embodiment of this kind may be implemented, for example, with a connecting arrangement which comprises a driving disk which is received by means of an internal toothing, with radial movement play and circumferential movement play, on an external toothing of the hub. A torsional vibration damper hub flange is coupled fixedly in terms of rotation to the hub. A spring arrangement with at least one spring extends approximately in the circumferential direction and is supported, in its end regions, on respective control edges of the torsional vibration damper hub flange, on the one hand, and of the driving disk, on the other hand. The at least one spring is displaceable in the region of support on the respective control edge of the driving disk and/or in the region of support on the respective control edge of the torsional vibration damper hub flange, with respect to the respective control edge, at least in the approximately radial direction of extent of the associated control edge.
Alternatively, it is possible for the connecting arrangement to comprise a driving disk with a radially outer disk part and with a radially inner disk part. The radially outer disk part has an internal toothing which meshes with an external toothing on the radially inner disk part with relative movement play in the radial direction and in the circumferential direction. The torsional vibration damper comprises a spring arrangement with at least one spring which is arranged in the region of the intermeshing toothings and which can be supported in its end regions on the external toothing, on the one hand, and the internal toothing, on the other hand. An arrangement which is axially very short is thereby produced, once again, which leaves increased construction space for other components or results in a general reduction in the construction space requirement for a friction clutch designed with a clutch disk of this type. In this case, preferably, the torsional vibration damper is arranged in the radially outer region of the driving disk.
Furthermore, radial displaceability and/or wobbling movability may be made possible solely or additionally by means of the elastic deformation of a coupling arrangement coupling the input side and the output side.
In this case, there may, for example, be provision for the input side to comprise a driving disk with internal toothing and for the output side to comprise cover disks which are arranged on both sides of the driving disk and which are connected fixedly in terms of rotation to the hub, the hub having an external toothing assigned to the internal toothing. In this case, there is preferably provision for coordinating the internal toothing of the driving disk and the external toothing of the hub with one another, in such a way that the driving disk and the hub are displaceable with respect to one another in the circumferential direction, in the radial direction and in the axial direction.
According to a further alternative embodiment, but one which can be combined readily with other embodiments according to the invention of an elastically coupling clutch disk, the connecting arrangement comprises a bellows-type coupling arrangement. It has been shown that, particularly in the case of torque transmission with axial offset and/or axial inclination, bellows-type coupling arrangements of this kind perform wear-free compensation of these axial errors and, moreover, have the advantage of extremely low mass.
In this case, for example, the bellows-type coupling arrangement comprises at least one coupling bellows which extends essentially in the direction of the hub rotation axis and which, in a first end region, is coupled to the hub and, in a second end region, is coupled to the friction linings. For example, the bellows-type coupling arrangement may comprise a metal coupling bellows.
The various features of novelty which characterize the invention are pointed out with particularly in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.